The present invention relays to intraocular lenses (also commonly referred to as IOLs), and more particularly relates to a thin IOLs that can be inserted through a very small incision in the eye and into the evacuated capsular bag of an eye.
Cataract surgery commonly involves removal of the eye's natural but clouded lens which is located in the capsular bag using a surgical technique known as phacoemulsification. It is desirable to have an incision in the eye as small as possible to improve heating and discourage formation of post-cataract astigmatism caused by the healed incision. The standard of today's incision size is 3 mm or less. With even more recent surgical techniques, i.e. bi-manual phacoemulsification or laser-phaco, incisions of less than 2 mm are possible. Of course if the IOL and/or the insertion instrument are larger than the incision size, the incision must be enlarged.
In order to pass a flexible IOL through a small incision, it must be compressed to a smaller size and inserted in the eye using an instrument such as forceps or an IOL inserter. Examples of IOL inserters may be seen in commonly assigned U.S. Pat. Nos. 5,944,725 and 6,336,932. It will thus be appreciated that the material and dimensions of the IOL will dictate how small the IOL may be compressed without undergoing damage (i.e., larger dimensioned IOLs will not compress as small as a smaller sized IOL). Of course, the IOL cannot be so small as to lose its intended purpose of restoring the function of the eye's natural lens. Proper functioning of the IOL requires the IOL to remain as stable as possible in the eye since movement thereof can distort the light rays passing therethrough onto the retina Positioning elements known as haptics are thus incorporated into the IOL design to help position and stabilize the optic in the capsular bag Many different haptic configurations exist yet there remains a need for an IOL of a relatively small size which allows the lens to be compressed and delivered through a small incision, preferably on the order of about 2 mm or less, while also maintaining the optic very stably in the eye despite compressive forces being applied thereto. Compressive forces may occur, for example, from shrinkage of the capsular bag which occurs in the few months following cataract extraction surgery.